Apparatus for seprating mixed materials having different electrical conductivities



Oct. 4, 1938. K, c. APPLEYARD ET-AL 2,131,930

APPARATUS FOR SEPARATING' MIXED MATERIALS HAVING DIFFERENT ELECTRICAL CONDUCTIVITIES Filed April 22, 1957 2 Sheets-Sheet 1 bit? I 78? A 75 a rg mm 5 2 p 4 21 flfgi w. 20

a/a ap /iji 'AL 2,131,930 TE LS HAVING US IFF Oct. 4, 1938.

K C. APPLEYARD ET FOR SEPARATING MIXED MA ERENT ELECTRICAL CONDUCTI Filed April 22, 1937 RIA VITIES 2 Sheets-Sheet 2 APPARAT D Patented Oct. 4, 1938. I

v r v 2,131,930 H v APPARATU S For: SEPARATING MIXED MA:

TERIALS HAVING DIFFERENT ELECTRICAL Q UQ E o r 7 v -Ken'elm' Charles Appleyard, Birtley, and Stanley -."-Dallas Pollitt, Newcastle-upon-Tyne, England,

.. assignors of one-third toThe Birtley Company x Limited, Birtley, England j. L Application April 22, 1937, Serial No. 138,454" a In Great Britain April 18, 1936 4 Claims. (01. 209-4 1) This invention relates "to'the separation,into ber employing a plate, like member and a hinged classes according to theirelectrical"properties, and helical spring controlled resilient mounting. of mixed materials, such as coal withjshale or According toFigures 1- to 4' of the drawings, other refuse and moreparticularly to automatipieces i of the material to be tested are fed in cally resetting devices" for making temporary single pieces at spaced intervals to an electri- 5 electricalfcontact withindividual pieces 'of' the cally conductive conveyor belt 2 upon which they material whilst the latter are moved past the are conveyed pasttwo contact devices 3 and 4 contact devices. V H V I V 7 respectively and delivered to a chute 5 and thence Coal separating machinesutilizing such devices to a selecting device not shown; but operated in *10 are describedun Britishfpatent specification No'. accordance with the eiiect upon an electrical 10 l 2 l,l0 l whj erein pieces of coal and stone are circuit associated withthe contactdevices 3 and fcausedto pass one cr more sets of resilient con- 4 of each piece of material as it passes them.

tact making jj dBVlCB S in the form of brushes, The contact device 3 comprises a brush like combs or'fingersjoperating sometimes in conmember having a stock portion 6 and a set of junction with a conveyor belt or the lik e of conflexible conductive Wires 1, and the above men- 15 ductivefm'aterial g ftioned electrical circuit is. completed when a In such cases the free length of the wires conpiece of. material passes beneath the member 3 V stituting the brush must be kept as small 'as andconnects, in a more or less conductive manpossible in order to reduceasfaraspossible the ner, according to its U electrical resistance the .20 overall size of the apparatus}, v member 3 with the conductive belt 2'as shown'20 Reduction of the length of "wire projecting in'Figure 3. I l, from the rigid .stock entails the risk that a large The contact device 4' comprises a pair of mempiece pi": material passing b'etween'them may .bers similar to the' member 3, but arranged as fbend them 'to'such an extent as to cause a permashown in. Figures 1 and 2 in such a waythat the 3 nentset in them. p h V flexible wires? are, disposed in a vertical plane y f Pieces of material may also. strike the wires but in a horizontal direction towards one anclose to the rootor anchoring point and thus otheiz' jIhese brushes l are hereinafter referred badly dnnagethem. p j i to as the horizontal brushes.

"'Ihe main objectof the invention isyto over- 7 The two sets of wires I approach one another come this disadvantage Fand other objects. and at their freeends but do not touch and the pieces 3 30 advantages with appearinthe following descripof material are conveyed on the belt 2 soas to tion. The invention.will' bepointed out in the bridge the gap 8 between them.

' Each of the elements L making ,up' a. Contact accompanyingclaims' 'I 'heiinvention willflnow, be described by way brush 3 or 4 is connected, as shown in Figure 4,.

of example, with referenceoto the accompanying to the common root or stock 6 by. way, of a resil- 35 drawingsin which: ient spiral part 9 which is protected against Figure 1 is a general view in elevation of a damage from the travelling pieces of material! conveyor belt and two sets of contact members. by being shielded by thestock of the brush. The

V Figure 2 is an end elevation of Figure 1. material is caused to pass from right to left in 40 Figure 3 is an end elevation of Figure 1 with Figures 1 and 4. Should a piece of material be 40 the foremost set of contact members removed. so wide as to reach close to the stock or be Figure 4 is a plan View of the foremost contravelling in such a direction as to strike against tact members in Figure l drawn to a larger scale the stock, then the spiral part 9 unwinds and to show the resilient springing of the fingers. takes the bending stress oiT the root of the ele- Figure 5 is a general elevational viewsimilar ment 1. 45 to Figure 1 but showing a conveyor belt which is In the form of the invention shown in Figure rendered conductive only from face to face by 5 the elements of'the brushes 4 are flexible in a plurality of inset conductors. planes which include the vertical with the result Figures 6, 7 and 8 are a plan and sectional that the lower elements of these brushes may 7 views respectively of the conveyor belt 01. Figtouch the belt, and effect undesirable results if 50 ure 5 to an enlarged scale. a the belt is completely conductive.

Figure 9 is a modified form of resilient mount- In order to avoid these results and to allow ing for the contact members. of setting the horizontal brushes 4 close to the Figures 10 and 11 are elevational views at right belt, in this form of the invention the conveyor angles of another modified form of contact-membelt 20 is made of rubber, vulcanized cloth or 55 other suitably strong electrically insulating material. Set into the belt are small hardened steel staples, rivets or studs of conductive material 2|, each electrically insulated from the other by'the material of the belt, and-resulting in a series of closely spaced contacts each making an electrical circuit through the belt, and each electrically insulated from the other. This construction is shown in detail in Figures 6, 'I and 8.

The drum over which the belt passes'is'made or faced with non-conductive material such as rubber so as not to short-circuit all the contact points 2! of the belt as it passes over the drum; Underneath the belt 20, directly underneath the vertical brush 3, a series of brushes 22 are fixed so as to make contact over a considerable area of the belt. These brushes are so arranged that they make contact with the conductive staples 2| on the underside of the belt, sufficiently far on either side of the vertical brush asto include the length of the largest piece of .material passing through the apparatus.

A circuit is thus completed vertically through any piece of material via the vertical brush, the piece of material, the conductive studs and the bottom brush. By the time a point of the belt reaches the horizontal brushes 4 which succeed the vertical one 3, it has left the'zone of contact of the bottom brushes 22. It is therefore possible .to set the horizontal brushes 4 down as close to the belt 20 as is desired because the studs immediately below them are insulated from earth and contact between the horizontal brush and the belt is of no consequence.

Figure 9 shows a zigzag or serpentine attachment 9 which may be used instead of the spiral form of resilient attachment shown in Figure 4.

In the form of the invention shown in Figures 10 and 11 the contacting membercorresponding to 3 above comprises a single defiectable element 1 in the form of a thin sheet of steel, aluminium or other suitable metal, hinged to the stockpart 6 on a horizontal axis lflby pivots ll so that it can swing forward and return under the action of the tension spring I2 on the tail piece I3.

The member I in this case may be formed as shown in Figures 10 and 11 of a replaceable wearing part I4, a permanent part I5 and the tail piece l3.

In a further modification the parts I in Figures 4 and 9 may be regarded as end views of a single sheet of conductive material provided with resilient means shown in Figures 4 and 9.

We claim:-

1. In apparatus for the separation of mixed materials according to the electrical conductivities of the pieces of material, a conveyor belt device having electrically conductive elements spaced therealong and extending from face to faeethrough thethickness of-thebelt and upon which the pieces of material. are adapted to be conveyed singly in series, a downwardly directed relatively fixed but resilient contact member, a

pair of laterally disposed contact members spaced apart and-arranged along the conveyor in a spaced relation. with respect to the downwardly directed contact member, and means for making continuous electrical contact with an area of the underside of the conveyor belt device immediately beneath said downwardly directed contact member.

2. Apparatus as claimed in claim 1, wherein the downwardly directed and the laterally disposed contact members each comprise a stock portion and an electrically conductive member projecting beyond the-stock portion. and lying in the path of the pieces of material, and resilient electricallyv conductive meansv connecting said conductive member and said stock portion positioned behind said stock portion so as to. be shielded thereby from passing pieces of material.

3. Apparatus as claimed in claim 1 wherein the downwardly directed and the laterally disposed. contact members each comprise a stock portion and an electrically conductive member projecting beyond the stockportionv and lying-in the path of. the pieces of material, and resilient electrically conductive means connecting said conductive member and said stock portionpositioned behind saidstock portion 'so as to be shielded thereby from passing pieces of material, and said resilient electricallyconductive means being of convoluted form. and integral with said projecting member.

4. Apparatus as claimed in claim. 1 wherein the downwardly-directed and the laterallydisposed contact members each comprise a stock portion and an electrically conductive member projecting beyond the stock portion .and lying in the path of the pieces of material, resilient electrically conductive means connecting said conductive member and .said stock portion positioned behind said stock portion so as to be shielded thereby from passing pieces of material, said resilient electrically conductive means comprising a convoluted wire integral with the projecting member, .and ,the convolutions of said wire being arranged in a single plane.

KENELIVI CHARLES APPLEYARD. STANLEY DALLAS POLLITT. 

